1. Field of the Invention
The present invention relates to a method and image generation apparatus that images and inspects an electronic device pattern at arbitrary positions on a sample using a critical-dimension scanning electron microscope (CD-SEM) or the like.
2. Background Art
Conventionally, critical-dimension scanning electron microscopes (CD-SEM) or the like are widely used to measure and inspect workmanship of a high-precision wiring pattern formed on a semiconductor wafer. Process micronization in semiconductor devices is currently advancing to an extent that 65 nm products are being mass-produced. As the process becomes finer, defects or the like to be inspected also become smaller and magnification in imaging cannot help but be increased. On the other hand, when carrying out a layout simulation of a wiring pattern, there is a need for conducting the simulation over a wide range. Furthermore, in order to conduct detailed simulations in the future, images are apparently preferred to be acquired at high magnification. However, when imaging is performed at high magnification, a part that fits into a screen becomes smaller, and the image cannot be seen over a wide range.
Furthermore, JP Patent Publication (Kokai) No. 2001-128106A proposes a method of acquiring an overall image at low magnification and then acquiring divided images at high magnification. According to this method, pasting positions can be identified for even a monotonous pattern with reference to the overall image. However, the overall image needs to be read at changed magnification. Furthermore, while imaging a mask causes no problem, imaging a wafer causes a problem with charge and when read once, the image may be disturbed, and therefore it is preferable to adopt a method that could avoid reading the overall image whenever possible.